Method for constructing a tunnel course, and structural element for use by the method

ABSTRACT

A method and a structural element for the construction of a directionally flexible and watertight tunnel lining ( 1 ) or tunnel course ( 1 ), the method using pre-fabricated elements of concrete or sandwich structure ( 3, 4, 5; 73;73 ′). Interspace between such elements and extending transversely of the direction of the tunnel course or tunnel lining receives an interspace cast ( 14 ) using an outer flexible formwork ( 2 ) in the form of skirts ( 2′, 2 ″) attached to the outside of the elements ( 3, 4, 5; 73, 73 ′), and which through interconnection ( 11 ) thereof form a flexible, “bag-like” formwork ( 2 ) on the outside of the elements ( 3, 4, 5; 73, 73 ′). Together with conventional formwork ( 12 ) on the inside of the elements ( 3, 4, 5; 73, 73 ′) there is formed a defined cavity ( 13 ) which can be filled with injectable mass of concrete. After the concrete has hardened it will provide support to the installed elements ( 3, 4, 5; 73, 73 ′) as well as providing support relative to exposed surface portion of rock surface ( 10 ). The elements ( 3, 4, 5; 73, 73 ′) can be provided on the outside with a membrane ( 17 ). Further, the elements can be provided with injection paths ( 16 ) in order to at any time establish a completely watertight tunnel lining ( 1 ).

The present invention relates to usage of pre-fabricated elements in adirectionally flexible and watertight tunnel course for special orgeneral use.

More specifically, the invention relates to a method for constructingtunnel courses which are completely or partly surrounded by rockformations and/or are located in open air, the tunnel course in itslongitudinal direction consisting of a plurality of mutually separate,pre-fabricated, preferably tunnel arch forming structural elements whichare intended to be sealed against each other or adjacent each other.Further, the invention relates to a structural element in order to applythe method.

Tunnel manufacturing technology is e.g. known from the following patentpublications: EP 0.197.021, GB 2.068.894, U.S. Pat. No. 4,895,480, DE4.014.437 and DE 3.210.529.

Traditional or special solutions for establishing tunnel linings ortunnel courses have in most cases highly limited possibilities tofulfill all required specifications simultaneously as regards costs,life, tightness, safeguarding against rock avalanche etc.

Apart from tunnels having full-profile drilling made using tunnel boringmachine (TBM), most tunnels are made using conventional drilling andblasting after adapted injection sealing of unbroken rock formationsfrom so-called “tunnel face”, followed by securing by means of rockbolts and sprayable concrete.

The configuration of the tunnel lining proper exhibits many variants.Concrete elements are known to be fixedly bolted at the sides with avariant of “umbrella” below the hang in the “ceiling”, which couldconsist of a flexible insulating plate and which later proved to haveshort durability and be highly inflammable, have subsequently beenattempted covered by sprayed concrete. It is however known that theserepairs, in a time perspective, still have a very short life, and aftera few tens of years most thereof is back to status quo. A preconditionfor this and all other known methods is extensive securing works in theform of bolt-work and possibly use of sprayable concrete, becauserequired inspection and status checking later is almost quite impossibleto perform.

Further, tunnel linings which include a movable material will representan inherent risk, because the protective layer over time may crack dueto fatigue and with the risk of drop-down or avalanche.

Tunnel courses which have been secured or made by means of sprayedconcrete fall into approximately the same risk pattern. The methodrequires as an outset an almost watertight rock space after blastingoperation, as it is challenging to spray concrete onto rock having waterleaks. However, in present days technological situation related tosprayed concrete, the situation is such that this by itself is notsufficient for satisfactory tightness in the structure, but almostalways requires additional safe-guarding measures against water andfrost. Ongoing research related to sprayable membranes appearsuncertain, and it is likely that the complete “spraying method” alsowill be quite expensive. Constructing a safe tunnel lining by means ofsprayable concrete is quite expensive and there are obvious limits tothe amounts of fiber loaded concrete that can be applied, withouttriggering a requirement for more traditional reinforcement.

Concrete in the context of tunnels is vulnerable due to leakages andbursting due to frost with subsequent disintegration of the concrete.Complete casting of a tunnel lining solves to a large extentrequirements related to securing of rock, but have obvious weaknessesrelated to tightness and expenses. A non-reinforced, fully casted tunnellining is highly vulnerable to leakages from formation of fissures andcracks due to quite often highly variable thickness of the tunnellining, which yields large local stresses in the concrete resulting incracking thereof. Repair thereof yields often an excessive demand forexpensive injection sealing of the tunnel lining later. Reinforcedtunnel lining is much more expensive, without any decisive guaranteeagainst formations of fissures and unacceptable leakages through theconcrete.

Fully covering tunnel linings have also proved to exhibit substantialchallenges. The sudden collapse of the ceiling of the Hanekleiv tunnelin the county of Vestfold, Norway some years ago is a typical example ofhow risky such a structure may be. Government authorities also emphasizethat there are substantial problems related to inspecting the securingof the rock in these tunnels, both as regards accessability and a healthhazard environment for the controlling personnel.

An external membrane on the tunnel lining, also sometimes as multiplelayers, as a foil between concrete and rock, presents a further turningof the screw of expenses. In addition, there is hardly any installationof membrane anywhere in the world which has solved the problems withouta time-consuming and frustrating search for stray leakages.

In order to remedy the problem, it is these days attempted to establishcomplex injection systems by means of injection hoses to section theproblems, which results in a wilderness of supply hoses which are likelydifficult to administrate.

In addition, membrane entrepreneurs set substantial requirements to thesmoothness and tightness of the surface, as welding membranes with waterflowing likely is no wanted situation. There are present “patentpending” solutions for a continuous casting of a tunnel lining, which isusually named as sliding formwork, although the method is somewhatdifferent. As far as known, none of these methods have been used inpractise.

In summary, it is an obvious and common feature of all known methodstoday that the tunnel after blasting operations and before the nextstep, should be 100% secured and be almost watertight.

The present tunnel technologies therefore face numerous challenges, eventhough data controlled drilling rigs, sophisticated injection techniqueand fiber-reinforced spraying of concrete have improved the conditionssubstantially for different solutions related to tunnel linings ofdifferent types. Still, within the technology of tunnels there has inmany aspects for a long time been a clear demand for novelconsiderations, for the purpose of solving all or most of the knownproblems. The expenses related to making tunnels are today prohibitivelylarge due to a deficient relationship between the technical problemswhich arise and the practical solutions.

The present invention aims therefore to provide technical solutionswhich fully or partly solve the deficiencies, also by using knowntechnique.

The method will prove to be highly cost efficient and the extent oftoday's expensive needs for securing by using installation of bolts,sprayable concrete and injection can be dramatically reduced. The tunnellining as a structure will be almost maintenance free and exhibit analmost ever lasting life; 300 years or more.

According to the invention the method mentioned in the introduction ischaracterized by:

-   a) installing along a tunnel course at each longitudinal side    thereof tunnel element bases and cast these onto masses adjacent the    bases,-   b) placing from recesses on the bases successively in the    longitudinal direction of the tunnel course with mutual distance    selfsupportive sections each consisting of at least two of said    tunnel elements, wherein the tunnel elements are made of concrete or    are of a sandwich structure,-   c) arranging at the outside of the sections at the opening    therebetween an outer, flexible formwork,-   d) arranging formwork equipment across the opening between the    sections at the inside of the sections,-   e) injecting concrete through the formwork equipment into a space    defined by adjacent tunnel element sections, said outer flexible    formwork and said formwork equipment, so that injected concrete    expands the outer, flexible formwork outwardly and laterally at the    outside of the tunnel course, and-   f) letting the injected concrete harden.

Further embodiments of the method appear from the sub-ordinate patentclaims 2-15.

Said structural element as mentioned in the introduction is primarilycharacterized in that the element on the outside at each edge thereofwhich is transverse to the longitudinal direction of the tunnel course,is provided with a first outer flexible formwork half which isconfigured to be interconnected with a corresponding second outerflexible formwork half on a neighbouring further element when thatfurther element is positioned next to said first element, to form aflexible formwork for receiving injectable concrete between theneighbouring structural elements.

Further embodiments related to this structural element appear from thesub-ordinate patent claims 17-25.

The invention is now to be described with reference to the attacheddrawings which exhibit non-limiting embodiments of the invention.

FIG. 1 illustrates characteristic use of an outer flexible formworkbetween arch elements and rock, or between base elements and rock.

FIG. 2 illustrates theoretical positions of the nets as the halves ofthe flexible formwork after the elements have been installed on theirrespective base elements.

FIG. 3 illustrates interconnection of the halves of the flexibleformwork at the outside of the elements and an inner traditionalformwork provided with a casting assisting pipe stub.

FIG. 4 illustrates a primary interspace cast between elements and rock,and secondary casting between elements and rock.

FIG. 5 illustrates in vertical view a situation with interspace castbetween elements and rock with varying mutual angle between some of theelements.

FIG. 6 illustrates in a horizontal view a situation with interspace castbetween elements and rock with varying mutual angle between some of theelements.

FIG. 7 illustrates an overall view of all structural elements includinga cast tunnel foundation.

FIG. 8 illustrates a tunnel embodiment located on gravel/rock in openair.

FIG. 9 shows a tunnel embodiment used for rehabilitation of existingtunnels having foundation on different beds.

FIG. 10 illustrates a possible method in making tunnel linings havingextensive cross-section.

FIG. 11 illustrates in detail mounting of an element base, interspacemould and drainage pipe/pipe for assisting casting.

FIG. 12 illustrates interconnection of formwork skirts and drainagepipe/pipe for assisting casting.

FIG. 13 illustrates in a vertical section joint and interconnection ofelement bases having sealing.

FIG. 14 illustrates a horizontal section of joint and interconnection ofelement bases having sealing.

FIG. 15 illustrates detail of horizontal contact between element basehaving injection paths moulded therein, joint mat and tunnel element.

FIG. 16 illustrates detail of horizontal contact between tunnel elementswith inserted joint mat and injection path.

FIG. 17 illustrates in principle an infiltration cushion which issectionwise dividable.

FIG. 18 illustrates in principle a general and immediate sealing ofjoints using infiltration cushions and spreader mat.

FIG. 19 illustrates in principle two types of injectable joint packing.

FIG. 20 a illustrates a grooved profile for formwork skirt part in aconcrete element.

FIG. 20 b illustrates in principle edge fitting fixedly pressed onto theedge of a net part.

FIG. 21 a illustrates formwork skirt part with edge fitting establishedin a grooved profile.

FIG. 21 b illustrates net part directly moulded into an element.

FIG. 22 a illustrates establishment of formwork skirt part which has amembrane applied thereto.

FIG. 22 b illustrates formwork skirt part moulded into a concreteelement with a membrane applied thereto.

FIG. 23 illustrates an installation situation for tunnel courseelements.

FIG. 24 illustrates an inside curved formwork for interspace casting ina cavity between elements and rock, and ventilation pipes at the upperhang-portion of the tunnel elements.

FIG. 25 a illustrates an electrified smoothing jetty at operatingpositions upon executing a step of deploying smoothing- and structuralconcrete at the tunnel foundation.

FIG. 25 b illustrates in principle individual drive units for asmoothing jetty resting on pivot pins.

FIG. 25 c illustrates in principle embodiment of a tunnel foundation bymeans of “bulkheads”.

FIG. 26 illustrates in principle anchoring of an electrified cranetrack.

FIG. 27 illustrates anchoring and suspension in elements for asectionally established crane track.

FIG. 28 illustrates tunnel elements of a sandwich structure in arrangedposition.

FIG. 29 illustrates tunnel elements of sandwich structure followingcomplete casting operation using a flexible formwork.

FIG. 1 illustrates the essence of the invention with all main components1, 1′, 2, 3, 3′, 4, 4′, 5, 5′, 6, 6′ 7, 7′, 8, 9 included.

Although the invention will be mainly described related to tunnel archforming elements made from concrete, it will be appreciated that suchtunnel arch forming elements could instead be in the form of lightweightelements made as a sandwich structure, as shown and described in thecontext of the embodiments shown on FIGS. 28 and 29.

FIG. 2 illustrates outer flexible skirt or formwork 2 which preferablycan be in the form of interconnectable net parts 2′, 2″ which are eachreliably attached in or along both vertical/upright edges of the archelements 3,4,5. In addition to the flexible formwork 2 having to possessthe required strength against breakage related to the use in question,the mesh width of the net parts 2′, 2″ must be somewhat less than thelargest diameter of the additives (stones) in the mass of concrete. Thisimplies practical aspects in the context known as using a particularmass for sealing of cracks known as clotting mass, implying that afterthe largest particles in the concrete no longer can pass through a meshopening, the continuously smaller particles in the concrete will come toa halt to finally block the entire passage, perhaps with the exceptionof leakage of water during a period. Such a flexible formwork 2 of nets2′, 2″ will thereby act as a reliable formwork 2, provided the nets 2′,2″ exhibit sufficient strength. The skirt, net parts 2′, 2″, 8, 9 can bemade from alternative materials, synthetic thread (nylon etc.), organicmaterial or steel wire etc. The flexible formwork, “the net bag” 2, mayif desirable, be constructed from multiple layers with a heavy dutyouter “bag” having large mesh width with an insert consisting of netmaterial having less mesh width or from another material havingcorresponding properties.

Following interconnection 11 of the two net parts 2′, 2″ at the openingbetween the elements 3, 3′ 4, 4′ 5, 5′ being adjacent in the tunneldirection, as shown in FIGS. 1 and 3, and co-operative with atraditional inner formwork 12, there is formed a cavity 13 which uponinjection therein of interspace mass in the form of concrete mass 14,see FIG. 4, will expand outwardly the flexible formwork or “bag” 2 untilit contacts the exposed rock surface 10 and the concrete will thussubsequently to hardening provide a very advantageous support for theinstalled elements 3, 3′ 4, 4′, 5, 5′ and masses of rock 10 along theentire cross-section of the tunnel. The formwork 2 simultaneouslyensures that the injected concrete is limited to the space of the cavity13 and is not spread in non-controllable way behind the elements 3, 4,5; 3′, 4′, 5′.

Water leaking in through the rock surface 10 behind the formwork bag 2during injection of concrete for establishing the interspace cast 14,will most likely after some wash-out of the concrete 14 at the frontupon direct contact with the rock surface 10 be pressed laterally andrepresent a reduced risk for unacceptable amounts of binder agent in theinterspace cast 14 being washed out.

Strong flows of water into the tunnel at locations where the interspacecast 14 is supposed to contact the rock surface 10, must in advance besealed or guided away in a satisfactory manner, e.g. by suspendingplastic material on the rock surface 10 or let a suitable length ofrelatively rigid plastic foil, in the form of a roll of plastics fittedonto reinforcing steel bar, from the top side “roll downwardly” over theopening between the elements 3, 4, 5; 3′, 4′, 5′, whereafter theplastics can be attached at the upper end before the net parts 2, 2′ areinterconnected at 11. Simultaneously with the plastics foil being movedoutwardly upon injection of the mass of concrete to form the interspacecast 14, it will protect the concrete against unwanted wash-out andguide leakages laterally, where the water in turn will disappear throughdrainage and casting assisting pipes 26, 26′ (FIG. 11).

There is on FIGS. 3 and 20 a-22 b illustrated attachment 18, 18′ of thenet parts 2′, 2″.

FIG. 4 illustrates the situation after the primary interspace cast 14has hardened and the mass of concrete has pressed the flexible formwork2 outwardly towards the masses of rock 10. Further, there is shown asecondary cast 19 between the interspace casts 14, 14′, the archelements 3, 4, 5 and the masses of rock 10. As it also appears fromFIGS. 15, 16, 20, 21 and 22 there are shown the membranes 17, 17′, 17″applied to the outside of the arch elements 3, 4, 5, recesses 15, 15′,and injection paths 16, 16′ moulded into the element edges which extendin a direction transversely of the tunnel course. It is obvious that theinterspace cast 14 and its contact face with the arch elements 3, 4, 5will be quite advantageous to obtain a completely water tightinterconnection, also upon supply of sealing mass through the injectionpath 16, 16′.

The situation shown on FIG. 4 also confirms that the transition betweenthe membrane 17, 17′ applied to the outside of the arch elements 3, 4,5; 3′, 4′, 5′ and the interspace cast 14, is obviously quite close andsolid and does not represent any uncertainty with respect to obtainingpermanent tightness against water in the connection between the archelements 3, 4, 5; 3′, 4′, 5′ and the interspace cast 14. It can not beexcluded that water may leak in through formation of fissures in theinterspace cast 14, but that problem must be solved locally throughinjection and does not represent any significant deficiency of themethod.

As shown on FIGS. 5 and 6 it is possible, by placing a plurality of archelements 3, 4, 5; 3′, 4′, 5′; 3″,4″, 5″; 3′″, 4′″, 5′″; 3″, 4″, 5″″ onthe same base elements 6, 7, to enable the tunnel lining 1 to be turnedboth in vertical and horizontal planes. Upon change of direction in thehorizontal plane as shown on FIG. 6, the length of one or both of thebase elements 6, 7 is adapted so that the required radius of curvatureof the tunnel course 1 is obtained, as indicated by the base elements orfoundations 6, 6′, 6″, 6′″ and 7, 7′, 7″, 7′″. It is preferable that thelength of the base elements 6, 7 is adapted so that the distance betweenadjacent arch elements, e.g. elements 5, 5′, along the center line ofthe tunnel always remains the same. The dimensions of the “wedge-shape”of the interspace cast 14 at the joints 23 of the base elements, may ifrequired be varied based on what is possible in practice or structurallydesirable. The width of the net parts 2′, 2″ will necessarily have to beadapted to the distance between neighbouring tunnel elements, e.g.elements 3, 4, 5; 3′ 4′, 5′, which are located in the direction of thetunnel course.

In order that the method in addition may be adapted to seamlesstransition for cambering at curves, it will be advantageous that the topelement 5 is not completely torsionally rigid, but to some extent mayadapt itself to the side elements 3, 4 on which the top element 5 shouldrest. The elements 3,4 will necessarily get a different direction attheir top, because opposed base elements 6,7 at respective sides of thetunnel course then will be located so that the free end of one baseelement 6 will be at a level different from the oppositely located baseelement 7. The top element 5, due to inherent elasticity in the element5, will within certain limitations adapt itself to the top of the sideelements 3,4. If this elasticity proves to be insufficient, it will inpractise be possible to allow additional forces to force the elements 3,4, 5 together at a joint 20-20″″ between arch elements (see FIG. 16) forthereafter permanently interconnecting the elements 3, 4, 5 by means ofplates 84-84′″ of steel moulded therein and connecting members 79, 79′welded thereto (as shown on FIG. 7) at a suitable distance from linearor radial edges of the arch elements 3,4,5.

Upon interconnection at the radial edges (not shown) of the elements 3,4, 5, the interconnection will with advantage be hided in the interspacecast 14. It is not likely that the elements, e.g. 3, 4, 5 will bestructurally damaged by such a rough handling if the effect of appliedforces lies well within pre-specified limits of tolerance. Even thoughthe side elements 3,4 and the top elements 5 on their outside arecovered by membrane 17 or have membrane 17 applied thereto, it will beappreciated that the membrane 17 will still be 100% intact after such anadaptation.

In a method as indicated, the side edges of the elements 3, 4, 5 willappear with a minor “stepping”, but this is considered unproblematic, asthese unevennesses are compensated by the inner formwork 12 and theinterspace casts 14-14″″.

A logic consequence of all of these conditions yields that the width ofthe interspace cast 14 may preferably also be varied to obtain differentadvantages, as increased width provides a wider and stronger interspacecast 14 which will provide better support of the masses of rock 10,whereas a more narrow interspace cast 14 first of all will reduce thevolume of concrete in the context in question. If the concept iscomplete casting, i.e. complete filling of the cavity with mass ofconcrete between the tunnel lining 1 and the rock surface 10, this playsmainly a minor role, except for the need for securing. Due to the natureof the invention, it will be unproblematic in the course of operation toreserve temporary open spaces in the tunnel lining 1 in order to laterbe able to install the missing elements 3, 4, 5, 6, 7 and establish thetunnel lining 1 as originally presupposed.

Further, it is of advantage that the elements 3, 4, 5; 3′, 4′, 5′ can bemanufactured with different radius of curvature or other preferredgeometry, and that alternatives of concrete concepts can be used, ase.g. normal concrete, light-weight concrete, concrete with sinteredparticles, porous concrete etc. The structural strength and degree ofreinforcement of the elements 3, 4, 5, 6, 7 are mainly related to theelements 3, 4, 5, 6, 7 being capable of handling from manufacturing tocompleted installation. Beyond this, some requirements will be that thata flexible formwork 2 is attachable to the outside of the arch elements3, 4, 5 and that a membrane 17 can be applied to the outside.

Further, FIG. 7 shows a tunnel lining 1, which contrary to prior arttechnology results in a completely watertight tunnel using only threedifferent, pre-fabricated concrete elements 3, 4, 5, however so thatdifferent tunnel cross-sections will require arch elements with adaptedradius of curvature.

The situation as clearly shown on FIG. 7, obviously createspossibilities for establishing a watertight tunnel foundation withmembrane between a smoothing concrete layer 25 and structural concrete28. Because the base elements 6, 7 will have very accurate mutualpositions, it will as shown in FIGS. 25 a, 25 b and 25 c be of advantageto deploy smoothing concrete 25 and structural concrete 28 by means ofmechanical equipment in the form of an electrified smoothing jetty.“Concrete bulkheads” 89, 89′ (as shown in FIG. 25 c) are established atrequired mutual distance and preferably corresponding to an interspacecast 14 from cleaned rock surface 10 and up to top edge of completedstructural concrete 28 of the foundation. There is placed between twobulkheads 89, 89′ a smoothing drainage layer of coarse gravel 90 with afelt cloth 91 on top thereof and with drainage 92 through last bulkhead89′, whereafter smoothing concrete 25 is deployed by means of thesmoothing jetty 58. A membrane 65 is placed or applied onto thesmoothing concrete cast 25 between the bulkheads 89, 89′ with adedicated termination along the edges, or also with an injection path.After the structural concrete 28 has also been deployed and has beensufficiently hardened, the drain 92 through the bulkhead 89′ is plugged,so that porous pressure behind the tunnel lining can increase. Further,it is preferable that the embodiment in question allows forestablishment of a radial injection screen 95 through the bulkhead 89′and the interspace cast 14 out into the masses of rock 10 which surroundthe tunnel lining 1 to reduce linear movement of water therealong,without touching laid-in membranes. Further, as shown on FIG. 7, it isadvantageous that a plurality of watertight covering pipes(pulling-through pipes) 81, 81′ can be established, located behind thetunnel lining 1 or be moulded also into the secondary cast 19 withradial projections 82, 82′ through the interspace cast 14 at suitabledistance. In case of fire or other serious incident, said establishmentwill be a very comforting safe-guarding of permanent installations orsupplies in along the entire course of the tunnel 1, e.g. signallingcables, emergency lighting, frost-free water supply or the like.

The water tightening at the connection between structural concrete inthe foundation 28, base element 6; 7, (see FIGS. 7, 12 and 15), andinterspace cast 24 between base 6; 7 and rock 10, can favourably betaken care of by injection through injection paths 16″″, 16′″″ mouldedinto recess 15″, 15′″ on the element bases 6, 7 being present as astandard, even on both sides of the element base 6;7. It obviously alsopossible to establish an injection path (not shown) on the smoothingcast 25 closely adjacent the interspace cast 24 as a further injectionoption.

As shown on FIG. 8, the method of the invention can without changes beused outdoors in open terrain as a tunnel for environmental purposes orfor safe-guarding against effects of avalanches. The method issubstantially the same as for a tunnel lining 1 inside a rock tunnel,but the installation of the elements 3, 4, 5, 6, 7 becomes much moresimpler, as it can be made using a mobile crane. As shown on FIGS. 11and 12 there is established element bases 6, 7 as for a rock tunnel orby letting bolts 34, 34′ for an anchoring tower 36, be located by meansof depositing sufficiently large lumps of concrete mass at the joints23, 23′, 23″, 23′″ of the element bases 6, 6′, 7, 7′. After the lumps ofconcrete have hardened, a top member 35 is levelled and is firmly weldedto the bolts 34, 34′. The element bases 6; 7 can thereafter be landedonto the top member 35 and be laterally adjusted before fixedly weldingthereof to the anchoring tower 36, 36′ takes place via steel platesmoulded into the bottom of the base 6; 7.

The support of the element bases 6, 7 relative to underlying terrain ispreferably made using conventionally reinforced concrete which caneither be filled around the element bases 6, 7 in a “ditch”, inconventional formwork or against a flexible formwork 8, 9 attached atlocation 18 into the base elements 6,7. A precondition for establishinga tunnel course 1 in open terrain is obviously that the fundamentationtakes place either on rocky ground or on compressed, notground-frost-risky bed. When performing “free” casting using “theformwork bag” 2, it will when filled with concrete mass necessarily geta somewhat different cross-section outside the tunnel elements 3, 4, 5.From the element bases 6; 7 and further up along the tunnel arch, thecross-section will vary from a circular shape to a gradually more ovalcross-section. This is however no problem, as the interspace cast 14thereby becomes preferably more huge at the “root” of the tunnel lining1 where the loads from any filling are the largest. If required, theinterspace cast 14 can here, as inside a tunnel in rock, be reinforcedmore or less, but this must be assessed in each case. As for tunnellining 1 in a tunnel in rock, the arch elements 3, 4, 5 have applied onthe outside thereof a membrane 17 which is considered satisfactory.

Sealing of joints vertically and horizontally between the tunnelelements can be executed as for the invention in general. In order tostabilize the arch elements 3, 4, 5; 3′, 4′, 5′ until the interspacecast 14 has been made and has hardened, it will have to be consideredwhether the elements 3, 4, 5; 3′, 4′, 5′ in addition must be supportedby stays. An obvious advantageous solution for stabilizing the elements3, 4, 5; 3′, 4′, 5′ would be to mould into these a plurality of steelplates on the inside along the elements 3, 4, 5 (see FIG. 8) adjacentlinear or radial edges (not shown) and connect these with connectingmeans 79, 79′ by means of welding.

Upon rehabilitation of tunnels in general and in particular roadtunnels, the invention can be implemented without extensive changes, asshown on FIG. 9. In principle, the element bases 6; 7 can be furtherused in a modified embodiment. A modified, low element base 29, 29′ isfixedly bolted to the foundation through a recessed position from thebottom of the “bearing” 22, 22′ (FIG. 11) and is established for eacharch section 3, 4, 5. This may be of advantage for continuouslyfollowing the tunnel path. The modified base 29, 29′ for the arch can beplaced on existing edge guides or on other bedding along the sides ofthe tunnel course. It may be considered whether there must be installeda plurality of rock bolts 31, 31′ via the interspace cast 14 tosafeguard against any risk for subsequent slide-out at the lower edge ofthe tunnel lining 1. In addition, all installations of the arch elements3, 4, 5; 3′, 4′, 5′ and the cast 14 are made as described for theinvention in general.

Crane track 68 with stay bolts 67, 67′ for the crane rail and associatedthreaded casings 30, 30′ for the bolts 67, 67′ can be installed, and anadvantageous formwork structure 12 can enable that the tunnel can bekept open for adapted traffic over prolonged periods of the day.

FIG. 10 elucidates a method for tunnels having an extra largecross-section. By positioning and make interspace casting 14 to(modified) arch elements 3, 3′; 4, 4′ using anchoring in the form ofrock bolts 31, 31′ to rock via the interspace casts 14, 14′, theelements 3, 4 at either side of the tunnel course can be stabilized andform a kind of foundation for the subsequent installation and interspacecasting 14 of (modified) top elements 5, 5′.

FIG. 11 shows a section of the “free end” of the element base 6,7attached to rock 10 via strong, fixedly fitted bolts 34, 34′. The bolts34, 34′ are fixedly fitted inclined towards each other and are, asmentioned earlier, interconnected with a top member 35 in the form of aheavy duty flat metal piece welded to the bolts 34, 34′ after the topmember 35 has been levelled into its individual position. The tolerancerelated to the positioning of the rock bolts 34, 34′ in the longitudinaldirection of the tunnel course must be such that the plate 33 which hasbeen firmly moulded into the lower region of the element base 6,7corresponds with and can be welded to the top member 35 which is mountedon the bolts 34, 34′. On the opposite “locked” end of the base 6; 7there is fixedly welded two strong supportive fittings 37, 37′ in theform of flat members on edge onto steel plates 32, 32′ which are mouldedinto the top of the bases 6; 7, such that half of the length of thefittings 37, 37′ protrudes out from the end of the base 6; 7. Afterlanding of the base element 6; 7 on an established anchoring tower 36for the base and the end of previous base 6; 7 and after aligninglaterally, the fittings 37; 37′ are fixedly welded onto the steel plates32, 32′ which have been moulded into the top of the base 6, 7 and thereis also welded between the anchoring tower 36 and steel plate 33 mouldedinto the lower part of the base 6, see also FIG. 13.

It will be appreciated that the base elements 6; 7 should, in aconventional manner be provided transversely and along their entirelength with reinforcement, and as indicated by reference numeral 39″.

Due to the favourable flexible formwork 8; 9, see FIGS. 1 and 12,concrete mass can immediately be supplied between base element 6; 7 androck 10 nearby. The net 8; 9 must necessarily be somewhat longer at bothends than the very base element 6; 7 and must on both sides be locatedand attached such that mass of concrete does not flow out at the ends ofthe base 6; 7. This implies that the net 8; 9 at the free end of thebase 6; 7 must be moved up to and be attached to the upper and outeredge of the base element 6; 7 for thereafter to be taken to the face ofthe rock 10 and fixedly attached thereat by bolting in a satisfactorymanner. This can be performed in a favourable way in that simultaneouslywith other welding operations, there is welded a “loop” onto the steelplates 32; 37 on the outer edges of the base elements 6; 7 where theindividual interspace cast 24 is to be terminated. The edge of the netpart 8; 9 is hooked onto the loops and led from the uppermost locatedone over to the rock surface 10 and fixedly bolted thereat.

At a location where multiple element bases 6, 6′, 6″, 6′″ . . . are tobe moulded into the interspace cast 24, 24′, 24″ . . . simultaneously,the ends of the net parts 8, 8′, 8″, 8′ are attached togethertransversely of the longitudinal direction of the tunnel course insatisfactory manner and will thus form a continuous flexible formwork 8;9. Before making an interspace cast 24 between base element 6; 7 andexposed rock surface 10, it is necessary to deploy the nets 8; 9 upalong the rock surface 10 and if necessary attach the nets 8; 9 to therock surface 10 at a plurality of locations by means of pegs 66, ifthere is a risk for the mass of concrete to “brush away” the nets 8; 9before mass of concrete in fact has landed on the nets 8; 9 and loadedthese nets. The friction between the nets 8; 9 loaded by mass ofconcrete and the rock surface 10 will soon stop the movement of the nets8; 9 down the rock surface 10 and mass of concrete can be supplied to adesirable level, which should lie somewhat below the top of the baseelement 6; 7. An obvious precondition is that the width of the net parts8; 9 is sufficient, and the width of the net parts 8; 9 should ingeneral be calculated from the attachment 18′ of the net parts 8; 9,vertically down to the rock surface 10 and up along that surface to aheight at the upper edge of the base 6; 7. Around the legs 34, 34′ ofthe anchoring tower 36, the net parts 8; 9 must be split forsubsequently to be joined together again in a sufficient way, or thatthe net parts 8; 9 are interconnected around the legs 34, 34′ of theanchoring tower 36 where the net parts 8, 8′, 8″; 9, 9′, 9″ . . .continuously continue.

It may be favorable in order to limit the use of net material 8; 9, andto make a safe and predictable cast work 24 between the base elements 6;7 and the rock 10, systematically to insert a plurality of “pegs” 66 inthe rock surface 10 before the base elements 6; 7 are installed. Thepegs 66 can favourably consist of short pieces of reinforcement steelbars which are put down into angled holes drilled a short distance intothe rock surface 10. After the base elements 6; 7 have been installed,the net parts 8; 9 are deployed up along the rock surface 10 and firmlyhooked onto the plurality of pegs 66, . . . which are located in thedirection of the tunnel course at suitable distance from the upper edgeof the net parts 8; 9.

In practice, it may prove advantageous that the drainage pipe/thecasting assisting pipes 26 are led through adapted holes in the net 8, 9and clamped to the rock surface 10 at their top, the end of the pipesbeing at sufficient height and possibly temporarily closed off. Aftercompletion of the cast 24 the pipes 26 can immediately be opened or becut to possibly lead away unwanted water flowing down onto the castconcrete 24. The pipes 26 are in any case later to be cut down so thatthey coincide with the upper face of the interspace cast 24, and so thatleakage water from the rock surface 10 down onto the interspace cast 24is guided away via the pipes 26-26′″.

The drainage pipes 26-26′″ should be dimensioned so strong that theylater and without problems can function as casting assisting pipes uponconnection to and injection of mass of concrete between the cast 24, 24′related to the base, the interspace cast 14, 14′ and the arch elements3, 4, 5; 3′, 4′, 5′

If the cavity between the arch elements 3,4,5 and the masses of rock 10is to be filled completely with mass of concrete, this must necessarilytake place while the drainage-/casting assisting pipes 26 are availablefrom the inside of the tunnel, i.e. before the tunnel foundation 25, 28is established.

In order to ease the making of the cast 24 between the base elements 6;7 and rock 10, it may be advantageous to arrange a wide and funnelshaped channel of concrete with rollers (not shown) and which is pulledon the edge of the base element 6; 7 to minimize spillage of concreteand to control the path of the concrete down closely adjacent the loweredge of the base 6; 7. In any case, the top of the base 6; 7 and thebearing 22 in the base element is cleaned and is possibly washed withwater while the concrete is fresh. If mass of concrete from theinterspace cast 24 or the net 8; 9 is found on the end of the last baseelement 6; 7, it must be removed completely before the next base element6; 7 is brought into position.

Advantageously, the invention permits that there can be installed manypre-fabricated base elements 6; 7 successively and that the cast 24which secures the base elements 6, 7 firmly to neighbouring masses ofrock 10 can be made without any need whatsoever for conventionalformwork, in view of instead using the nets 8; 9.

Further details shown on the section (see also FIG. 15) is “the bearing”22 for tunnel elements 3; 4 in the base 6; 7. The bearing 22 hassemi-circular cross-section, and the centre of the bearing 22 can be asomewhat lowered relative to the top of the elements 6; 7 and withtangentially opposite differing sides, something which permits that thetunnel element 3; 4 with its semi-circular shaped lower end can betilted a few angular degrees, implying that the arch elements 3; 4 canbe moved forwards and backwards at the top of the elements 3, 4.

The radius of curvature of the bearing 22 for the base element 6, 7 mustnecessarily be somewhat larger than the radius of curvature of thebottom of arch element 3, 4.

On FIG. 12 is shown a vertical view of element bases 6, 6′ and thepositioning of arch elements 3, 3′; 5, 5′ onto these bases 6, 6′. Thelength of the element base 6; 7 can vary, but it is in general ofadvantage that the length of the base 6; 7 is adapted to the width ofthe element, so that it is preferably obtained same distance between theelements 3, 4, 5; 3′, 4′, 5′. All individual elements 3, 4, 5, 6, 7; 3′,4′, 5′, 6′, 7′ are normally made identical, so that all in principle canbe used interchangeably in end reversed position (see also FIG. 1). Thewidth of the interspace cast 14 can be adapted to the need for spaceupon interconnection 11 of the nets 2′, 2″ or be increased beyond thisto establish an extra strong interspace cast 14 for securing the massesof rock 10.

If it calculationwise or based on experience proves necessary to preventlateral slide-out of the arch elements 3, 4, 5 by injection of concretemass for the cast 14, there can favourably be placed one or moretwo-piece anchoring bolts 38, 38′ from threaded casings fixedly mouldedin the elements 3, 4; 3′, 4′, and which later are welded together atlocation 38″.

On the vertical view there is further illustrated interconnection 11 ofthe neighbouring net parts 2′, 2″ which together will constitute theflexible formwork “bag” 2. Due to the obvious situation in the openingbetween the arch elements 3, 3′; 4, 4′; 5, 5′ and the net parts 2′, 2″,it will be favourable to pull the net parts 2′, 2″ in through theopening between the elements 3, 3′; 4, 4′; 5, 5′, place the net parts2′, 2″ against each other as shown on FIG. 3 and bind the net parts 2′,2″ together at that position to create the interconnection 11. However,it will be obvious that the net parts 2′, 2″ can be joined together eventhough the distance between the elements 3, 3′; 4, 4′; 5, 5′ is quitesmall and the limit is apparently in that it becomes practicallypossible to inject concrete for the interspace cast 14. After the netbag 2 has been put back between the elements 3, 3′; 4, 4′; 5, 5′, theformwork 12 can be positioned and the making of the interspace cast 14can take place.

The interconnection 11 can obviously be solved through alternativemethods, but the preferred one is to “sew” together the net parts 2′, 2″by means of e.g. steel wire 11 or other interconnection means, which isof the same length or somewhat longer than the total length of the netparts 2′; 2″. Onto the end of the steel wire 11 can be fitted a needleof suitable length, and the wire 11 can likely favourably be threadedthrough the net parts 2′, 2″ from the top of the arch and downwards atboth sides, by letting the wire 11 run over a pulley (not shown)temporarily hung onto the edge of the top element 5, 5′.

After interconnection of the net parts 2, 2′ in the opening between thearch elements 3, 4, 5; 3′, 4′, 5′, the respective ends of the wire 11must be anchored in the respective base elements 6; 7 in that it is as astandard procedure made an minor cut-out or “loop” 43 at the middle ofthe members 37 (see FIGS. 12, 13 and 14) where the wire 11 can be pulledthrough and be secured, or directly be interconnected about thesupportive, fitting members 37.

Midway in on the base element 6, 7, the wire 11 can be anchored in thesame manner by fixedly welding a supportive member 37 to a steel plate85 moulded into the top of the base 6, 7. Alternatively, there can befixedly welded a loop (not shown) to that same plate 85 where the wirecan be anchored in a safe way. Independent of how the wire 11 isanchored, it is very important that the net parts 2′, 2″ are joined insuch a manner that there is created a tight “bottom” in the formwork bag2 completely in towards the outer faces of the arch elements 3, 3′; 4,4′ and that it is shaped so that the “bottom” of the bag 2 may rest onthe top of the interspace cast 24.

Transverse joining interconnection 86 (see FIG. 8) of the edges of thenet parts 2′, 2″; 2′″, 2″″ in the direction of the tunnel course canalso take place through alternative methods, also using wire, but thecurrently preferred best mode will be to hook together the created nettype flexible formworks 2 using “closed” loops of steel which are sospacey that some required net material can be accommodated within theloop. Due to the location of the transverse joints 86 in heightdirection considered, the stress on the net-based formwork 2 duringinjection of concrete mass for the interspace cast 14 will here be farless than the stress at the bottom of the net bag 2 resting on theinterspace cast 24.

In the base elements 6, 7 there must be included embedded articleshaving specific tasks. In the bottom of the base 6; 7 there must, aspreviously indicated, be embedded (moulded in) sufficiently large andanchored plates 33, 33′ of steel at the ends of the base 6; 7, as wellas embedding (moulding in) at the top and ends of the base 6; 7 thepreviously mentioned plates of steel 32, 32′, 32″, 32′″. At the midregion and top of the bases 6, 7 there must be embedded (moulded in)plates 85, 85′ of steel for firmly welding of a heavy duty slab or flatmember on edge corresponding to supportive member 37 as bedding for thefoot of the curved formwork 12 and pivot bearing 55. Further, it must bemoulded into the bottom of the base element 6; 7 a recess profile 39′for attachment of said skirts 8; 9, as will be more closely explained.Even though all embedded (moulded-in) units are not used in eachinstallation situation, it will be quite advantageous that the baseelements 6, 7 are symmetric about both axes of the base elements 6, 7.This yields much better flexibility, because fitting 18′ of the netparts 8, 9 and the steel plates 32, 32′ on the top of the base elements6, 7 for establishing of a fitting for the foot of the curved formwork12, will not require any attention and control before the base elements6, 7 must be directionally oriented before transport into the tunnelcourse, as the length of the elements 6, 7 in some cases possibly doesnot permit a turnaround of the elements 6, 7 inside the tunnel course.

The element bases 6,7 can with advantage be moulded and transported“upside-down”, preferably with lowered lifting devices (not shown)moulded into the underside of the element bases 6,7, as this will alsoease storage of the elements 6, 7. This is also preferable because thismust necessarily be the position of the element 6; 7 when the formworkskirt/net 8; 9 is to be fixedly inserted at attachment location 18. Thenet 8, 9 to be used for fixing the element base 6; 7 through use of theinterspace cast 24, may have far less strength against breakage than thenet parts 2′, 2″ associated with the arch elements 3, 4, 5; 3′, 4′, 5′and the attachment 18′ in the base elements 6, 7 can likely be madeusing a rapid hardening, expanding mortar.

If the base joints 23-23′″ are to be completely watertight, then thereis in FIGS. 13 and 14 shown a favourable method, in that both ends ofthe base elements 6, 7; 6′, 7′ during manufacturing are made with a“shallow” semicircular recess 41, 41′ for a sealing plug 42 downwardstowards the bottom of the element 6, 7, so that when two base elements6, 6′ are joined together, there is formed a cavity having a “bottom”.The joint 23 between the element bases 6, 6′ can thus advantageously besealed by filling of expanding mortar or e.g. liquid asphalt which formsthe sealing plug 42. It will be advantageous to install a self-adhesivepacking of foamed rubber or rubber on an end of the base elements 6, 7and around the recess 41 immediately before locating a new base element6, 7, in order to prevent sealing mass forming the plug 42 from leakingout from the cavity.

As shown on FIG. 16, all joints 20 in the direction of the tunnel courseand located between arch elements 3, 4, 5 are favourably provided withinjection paths 16′″ moulded into the elements 3, 4, 5 and which can beinjected with a suitable sealing mass as may be required.Correspondingly, for joints between interspace cast 14 and adjacentelements 3, 4, 5; 3′, 4′, 5′ there may in the elements be providedmoulded-in injection paths 16; 16′ which can be injected with suitablesealing mass as may be required. Injection paths 16″ for injection ofsealing mass as may be required can be present in the bases betweenelements 3, 4; 3′, 4′ and adjacent base 6, 7; 6′, 7′.

In FIG. 15 is also shown an open-pore, compressible and injectable“joint mat” 44 which is located in the connection between the archelements 3; 4 and the base 6; 7, and in FIG. 16 is shown a corresponding“joint mat” 44′ at the connection between the arch elements 4; 5. Bymeans of these it is achieved that the sealing material is “reinforced”and in practise will appear as an on-location moulded packing havinglong life. A cheap and efficient joint mat 44, 44′, as e.g. shown FIGS.18 and 19, can e.g. consist of mineral wool, glass wool or the like(Rockwool®, Glava®, etc.).

Alternatively, the sealing between sections of the arch elements 3, 4, 5and/or arch element 3; 4 and base 6; 7 can consist of a closed-pore,compressible plate 45 having through-going perforations (as shown onFIG. 19), which also due to the perforations will be injectable becausesealing mass favourably upon any injection can spread to both contactfaces via the perforations. Such a “joint packing” 45, 45′, as indicatedon FIGS. 18 and 19, can e.g. be a flexible plate of closed-pore cellularrubber or of plastics with through-going perforations. The joint package45, 45′ should primarily be watertight after installation of theelements 3, 4, 5, but can also be further sealed via the respectiveinjection paths 16″; 16′″ in sides of the elements 6, 7; 3, 4 extendingin the direction of the tunnel course, i.e. “linear” sides.

As shown on FIGS. 11, 15 and 16 it will, due to relatively short lengthsof the injection paths 16″-16′″″ be likely that the injection paths canbe injected via supply hoses 77-77′″ which have been installed at themiddle of the hose sections via a T-piece and which thereafter are ledto the air side (tunnel course side) of the elements 3, 4, 5, 6, 7 andare terminated inside a lid provided plastic cup 78-78′″ moulded intothe elements and which later is exposed in the surface of the concrete.The supply hoses 77-77′″ can favourably be arranged as shown on thecross-sections and are easily secured during the process of moulding byattachment to the reinforcement in the element.

If the injection paths 16″-16′″″ are to be re-injectable, then supplyhoses 77-77′″ must be established at both ends of the respectiveinjection path 16″-16″″ and led to the air side (inside) of all elements3, 4, 5, 6, 7.

Corresponding solution with supply hoses and plastic cup cancorrespondingly be provided for the injection path 16; 16′ on thoseedges of the elements 3, 4, 5 which are oriented transversely of thetunnel course.

A method for immediate water tightening of the element connections 20,21 as shown on FIGS. 17, 18 and 19, is the introduction of “infiltrationcushions” 46, 46′ containing a single-component sealing material(Polyurethane (PUR) or the like) which is placed below or above the“joint mat” 44, 44′ and which will crack and release adapted andsufficient amount of sealing mass as soon as the arch elements 3, 4, 5are lowered into position. The mat 44, 44′ will thus function like a“wick” which attracts sealing mass and yields an almost immediatesealing as the sealing mass over time is exposed to moisture. By fixedlygluing a suitable package 47, 47′ or by using a self-adhesive version inthe region of the edge of the element 3, 4, 5, the sealing mass willefficiently be held in place without flowing out in axial direction.

Injection paths 16-16″″ for injectable sealing mass should still beimplemented in the elements 3, 4, 5, 6, 7 as indicated to ensure anabsolute possibility for supplemental tightening in a rational fashionat any time. The infiltration cushions 46, 46′ (see FIGS. 17 and 18) canbe manufactured in a favourable plastics quality, possibly chemicallydegradable in the operative environment in question, provided insuitable lengths with a short and empty inter-space 46″, so that thearray of infiltration cushions 46, 46′ can be cut away from each otherand be adapted to lengths in question.

The superior object of locating a joint mat 44, 44′ or joint packing 45,45′ is to make the joints 20, 21 between the elements 3, 5; 4, 5; 3, 6;4, 7 as compact as possible and simultaneously optimum injectable inthat the sealing mass is reinforced and is also favourably spreadable inthe entire width and length of the joint 20, 21.

The requirement related to the technical properties of the injectionpath 16, 16′ (see FIG. 4), is that it primarily can withstand theoutside water pressure which will arise in the mass of concrete of theinterspace cast 14 when concrete mass is injected into the cavity 13,without the injection path 16, 16′ being infiltrated or damaged in thecourse of the process. It is also important that the injectionpath/injection hose 16, 16′ has such a cross-section and surfacestructure that the injection path 16, 16′ can get a good grip in theconcrete surface and be satisfactory exposed to the surroundings.

Stabinor AS, Lier, Norway manufactures an injection hose which meets, bya good margin, all requirements in question related to such devices.Tests made in pressure chamber confirm that the injection hose resistsan external water pressure of 5-6 bars without the injection hose beinginfiltrated by water in the chamber. The injection paths 16-16′″″ mustby means of suitable devices be attached/installed on the formwork partswithout the hose being affected in negative way when the formworks aredisassembled.

The net parts 2′, 2″; 8, 9 can be attached in alternative ways, alsopurely mechanical. FIGS. 20 a-22 b illustrate a method for safeattachment fitting 18 of the formwork skirts/net parts 2′, 2′ at theedges of the arch elements 3, 4, 5 and which distributes the stresses onthe net parts 2, 2″; 8; 9 at the attachment fitting 18 in an excellentway. As shown on FIG. 20 a there is established a profile 39 of plasticsor sheet metal at sufficient distance from the edges of the elements 3,4, 5; 6, 7 (see also FIG. 11). With a profile 39 made with favourablecross-section, the method may further imply that there is at theconstruction site made a casting in place at location 18 of the edge ofthe net parts 2′, 2″ by means of a strong, rapid hardening mortar. Byfixedly pressing into position shortened lengths of edge fitting 94,94′, 94″ . . . on longitudinal edges of the net parts 2′; 2″, moreeasily a positioning and securing can be made. By turning the edgefitting “upside down”, the net parts 2′; 2″ can be pulled into therecess-profile 39 from the end, whereafter the edge of the net isretained in the profile 39 because the width of the profile does notallow the edge fitting 94 to rotate back to original position. It isalso advantageous that the strength and the width of the skirt 2′, 2″can be adapted to on-site conditions in order to avoid excessive use ofnet material. The moulding into place 18 of the net parts 2′, 2″ shouldbe made with the net parts 2′, 2″ in the same position as shown on FIG.21 a, because the net parts 2′, 2″ then will be in almost the sameposition as when executing the interspace cast 14 (see FIG. 4). In asmaller recess 40 for the net parts 2′, 2″ at the end of the recessprofile 39, the net parts 2′, 2′; 2″, 2″ can be pulled inwardly towardsthe tunnel course upon the installation of the arch elements 3, 4, 5, sothat the nets 2′, 2″ as such will not represent any bar against thecontact between the arch elements 3, 5; 4, 5. As shown on FIGS. 21 b and22 b, the net parts 2′; 2″ and 8; 9 can be moulded directly into thearch elements 3, 4, 5 and the bases 6, 7 (not shown). Even in thissituation it may be advantageous that the net is provided with edgefitting 94 as the net more easily can be distributed correctly over thelength and be attached.

A corresponding solution, such as shown on FIG. 11, is available forattachment 18′ of the net parts 8; 9 at the lower edge of the bases 6,7. Thus, there must be established a recess 40′ at the termination ofthe recess profile 39′ which at the lower edges of the base element 6, 7is moulded therein.

Further, the drawing figures (see also FIGS. 2, 3, 4, 15 and 16)illustrate that at a suitable point of time in the process, i.e. aftermoulding the arch elements 3, 4, 5; 3′, 4′, 5′, but before installingthese in the tunnel course, a membrane 17 is applied to their outside.The membrane 17 may be a sprayable or smearable membrane or a method maybe used where a membrane cloth is tacked to the surface of the element,possibly using a sprayable or smearable membrane as glue. At a locationwhere it is made a contacting cast between the arch elements 3, 4, 5,the interspace casts 14, 14′, the interspace cast 24 and the rocksurface 10, the membrane 17 will obviously be tightly surrounded byconcrete on both sides and quite well protected, with a life onlylimited by the properties of the membrane material as such.

The elements 3, 4, 5; 3′, 4′, 5′ may if desirable, also in advance, getan inner coating or paint applied, which after cleaning of the concretesurface can obtain good adhesion and life duration, and ease cleaningand reduce carbonatisation of the concrete, although this in the contextis less important as the reinforcement in the arch elements 3, 4, 5after completion of the tunnel lining 1 has reduced importance and inaddition has large coverage.

FIG. 23 illustrates a typical installation situation for the archelements 3, 4, 5. After the arch elements 3, 4, 5 in a satisfactorymanner have been moved into the installation area, they are handled byan installation machinery 52 provided with vacuum equipment 51, e,g.vacuum plate, which connects to, can lift and support all loads inquestion at all positions. The side elements 3, 4 are installed firstand are supported temporarily by raising from the tunnel bottom one ormore supports 48, 48′ using an incorporated hydraulic jack having shortstroke—for safety reasons—to an articulated transition on a self-locking“grip shoe” 49 which is entered on the elements 3, 4 from the edgethereof. After both side elements 3, 4 have been positioned andsupported at their respective “spreaded” positions, there is applied tothe top element 5 from the edge thereof a plurality of self-locking“guide shoes” 50, 50′ which are attached to the element 5 by means ofset screws. The top element 5 (constituting a locking element) isthereafter brought up to a suitable position between the side elements3, 4. The side elements 3, 4 are thereafter by slight turning lowereddown onto the guide shoes 50, 50′ and most of all weight or all weightfrom the side elements 3, 4 is transferred to the guide shoes 50, 50′,whereafter the installation machinery 52 lowers all elements 3, 4, 5slightly and simultaneously into final position, in order that theseelements find their mutual self-centering contact faces and form asatisfactory stable selfsupportive entity, whereafter the guide shoes50, 50′ should be removed prior to making the interspace cast 14 and theinterspace cast 19 to form a final tunnel lining 1.

In the course of the installation process a possible positioning of thejoint mat 44, the infiltration cushion 46 or joint package 45 must takeplace in a practical and acceptable manner.

After the elements 3, 4, 5 have assumed their final positions, theelements 3, 4, 5 jointly form a satisfactory stable structure until theinterspace cast 14 has been made. The elements 3, 4, 5 do not haveparticularly much space for larger movements until the time for theinterspace cast 14, but the elements 3, 4, 5 may in a simple manner byusing wood material be blocked up against the rock surface 10 behind theattachment 18 of the net parts 2, 2′.

Thereafter, it is ready for interconnection 11 of the flexible net parts2′, 2″ and installation of the inside formwork 12. If the elements 3, 4,5 in practise do not obtain completely accurate mutual position in thelongitudinal direction of the tunnel course, this has reduced importanceas the formwork will cover sufficient area for making the interspacecast 14.

The installation machinery 52 for the arch elements 3, 4, 5 canpreferably be movable on wheels, with a short and strong telescopic armhaving rotation and tilt properties and a quick-coupling for attachmentof the vacuum equipment 51 which connects to the arch elements 3, 4, 5.The installation machinery 52 may advantageously be placed on athree-axis frame controlled dumper chassis (not shown) with hydraulicsupporting members for use when connecting to the elements 3, 4, 5and/or during the installation phase. Further, the chassis should beutilised in such a way that there at the sides or at the rear can bearranged a “cradle” where the elements 3, 4, 5 can be provided withsupport during movement. Upon deconnection of the vacuum equipment 51,the installation machinery 52 may favourably also be used for othertasks with suitable equipment using the quick-coupling.

FIGS. 3 and 24, also with some structural details, illustrate inprinciple the inside formwork 12 which can favourably be made as alight, two-part, dividable and hinged framework structure which is fullyor partly self-erectable by means of pneumatic cylinders 54, 54′ whichthrough advantageous use also can erect the curved formworks 12, 12′during the first phase of the installation. The curved formworks 12, 12′are catched manually at the top and are connected by means of one orpreferably two hydraulic tensioning devices 53, 53′ and which afterapplied tension are also secured in a mechanical way. The obviousadvantage of using two separate tensioning devices 53, 53′ is that thetensioning forces thereby can be directed directly into the bottom boomson both sides of the framework of the curved formworks 12, 12′.

The foot of the curved formwork 12 may favourably be provided as apivotal bearing 55, 55′ having its base on existing fixedly weldedsupportive members 37, 37′ at the joint 23 of the element base 6, 7; 6′,7′ or to be attached “supportive members” 37″, 37′″ welded onto steelplates 32 at the middle of the base 6, 7. The supportive members 37,37′, 37″ will in addition have an accurate positioning and will togetherwith the moulded-in steel plates 32, 32′, 32″ . . . at the top of thebases 6, 7 straight away carry the loads which the tensioning of theformwork 12 yields.

Further, it is advantageous that the lower part of the formwork 12, 56;12′, 56′ with concrete supply stub 80, 80′ are separate andindependently installable and uninstallable towards the outside of thecurved formwork. It will ease the releasing of the formwork 12, 12′ ifthe stub 80, 80′ with surrounding formwork plate 56, 56′ can be releasedfrom the curved formwork 12, 12′, and remain sitting on the concretesurface when the curved formworks 12, 12′ are lowered. In such a manner,the formwork plates 56, 56′ can be detached later and thereafter beinstalled back on the curved formworks 12, 12′ before the curvedformworks 12, 12′ are erected the next time.

The formwork skin on the curved formworks 12, 12′ may preferably be madefrom a light and strong material having a replaceable coating on theoutside. The method may presuppose that a plurality of pairs of curvedformworks 12 are available, so that longer sections of the tunneladvantageously can simultaneously be provided with interspace casts 14.The formworks 12, 12′ may favourably be moved directly to next locationor be stored in folded configuration.

In order that contacting cast 19, see FIGS. 4 and 29, between archelements 3, 4, 5 and rock surface 10 can be made in a predictable andgood manner, it will be advantageous to install a plurality of pipes57-57″ . . . at the top of the “hang” behind the interspace cast 14 forevacuation of water and air when making the interspace cast 19. Thepipes 57-57″ . . . may favourably have an internal diameter in such amanner that added material in the concrete of the interspace cast 19after a short time automatically will block the pipes 57-57″ . . . whenthe concrete of the interspace cast 19 reaches the top.

Due to the obvious possibilities offered by the invention to establish atunnel lining 1 with a high degree of accuracy, also between oppositeelement bases 6, 7, it will be advantageous to develop mechanicalequipment for smoothing the tunnel foundation 25, 28 (see FIG. 7) whereit is to be cast and preferably be watertight. As shown in FIGS. 25 a,25 b and 25 c the equipment can comprise electrically powered units 60,60′ with drive wheels 59, 59′ which carry a smoothing jetty 58 runningon rollers 93 within a steel profile 94 bolted onto supportive members37 on edges of the element bases 6, 7. The propulsion can with advantagetake place using a gear interacting with a rack attached to the upperside of the steel profile 94 or through a rubber coated wheel havingspring tensioning. The jetty 58 can advantageously be built as aframework structure as depicted by FIG. 25 a. By giving the carriage(jetty) 58 independent propulsion from the motors 60, 60′ and arrangethe smoothing jetty 58 on pivot pins 61, 61′ at both sides, it will bemaneuverable safely on the edges of the base elements 6, 7, even atcurves and at inclinations, in that the jetty 58 normally will notpossess total torsional rigidity and also can be granted a certainlateral staggering tolerance. By providing the jetty 58 with a pluralityof movable, inclined and adjustable “wings” or articulated transportscrews (not shown), a variable, vibrating “smoothing board” 87 can beattached to rubber dampers at the side of the bottom boom 88 of thejetty 58. The concrete for the foundation 25, 28 will thus be able to betransported outwards and up at the sides with reduced need for manualhandling. The smoothing jetty 58 can be adapted to level of thesmoothing cast 25 and the structural concrete 28, respectively, bymoving the jetty 58 in vertical direction via an adjustable device whichalso by means of a slide could be operated in stepless fashion via amotorized spindle. When the smoothing jetty 58 is not used, it may bereleased from the pivot pins 61, 61′, be lifted and placed along thetunnel lining 1, while the propulsion units 60, 60′ can still remain onthe edges of the base elements 6, 7. If there favourably has beeninstalled a crane track 68 in the tunnel course, it will at the time forcasting of the foundation be operative and could be used for immediatedisplacement of the smoothing jetty 58. The crane track 68 can alsoadvantageously be used in connection with casting of the foundation 25,28, e.g. by one or more travelling carriages 69, 69′ . . . by “loose”rollers (not shown) hooked onto the crane rail 68, keeping up andcontinuously allowing to position the injection hose for concrete fromabove and downwards right in front of the front of the smoothing jetty58, also by being able to move the injection hose laterally out to thesides and contribute to placing the concrete in a precise manner overthe entire width of the bottom of the tunnel.

The logistics related to transporting elements 3, 4, 5, 6, 7 into thetunnel, can as regards the element bases 6, 7 be solved throughtransporting therein and deploying by means of a crane fitted vehicle.It will be advantageous if it in advance has been established andlevelled a plurality of anchoring towers 36 (see FIGS. 13 and 14) forthe base elements 6, 7 and where the base elements 6, 7 successively canbe landed, oriented and fixedly welded into their individual positions.

FIGS. 26 and 27 indicate a transport solution for tunnel arch formingelements 3, 4, 5 from open air and in towards the location forinstallation.

The crane track 68 is electrified and modular, and is—asmentioned—equipped with at least one travelling carriage 69, where thecrane rail 68 successively is installed via stays 67, 67′ from threadedcasings 30, 30′ cast into the arch elements 5 at suitable distance fromthe edges thereof in order that the interspace cast 14 (see FIG. 27)also can contribute to stabilization of the tunnel lining 1 and thefitting of the crane track. One or more travelling carriages 69 having awinch 83 can be remotely controlled and quickly bring a larger number ofelements 3, 4, 5 in towards wanted location for installation and suchthat the elements therefrom can be collected by means of theinstallation machinery 52. In practise, it is advantageous to transportelements 3, 4, 5 into the tunnel when there is little traffic and storethe elements 3, 4, 5 in a standing position along the tunnel lining 1,e.g. during a period for drilling in preparation for a new blastingoperation. It is however obvious that transportation of elements 3, 4, 5in the indicated manner always can take place within a region of thecross-section of the tunnel which is not obstructed by otherinstallations, except for other transport activity, viz. the region inthe middle of the cross-section of the tunnel.

Other advantages of a crane track 68 is that it also can be used forother kinds of transport and that it is directly re-usable. Theattachment devices 30, 30′ for the crane track 68-68″ can later be usedfor other permanent installations in the tunnel, e.g. armatures forlighting. The travelling carriages 69 with winch 83 may be operated byradio control, be provided with warning light/signal and automatic stopat obstructions located at regions of work. On FIG. 26 there is alsoindicated some temporary installations like ventilation pipes andsuspension means for cables and pipes. As it most likely that a tunnellining 1 successively will be established close to tunnel face, it ismost likely that the forwarding of said temporary installation mainlyfollows just behind the progress of the tunnel lining 1, but in such away that hoses and cables over a period will lie on the tunnel bottomfrom the established tunnel lining 1 and onwards to tunnel face.However, it will be appreciated that required temporary means fordelivery of electric power, water, pressurized air and ventilation willnot present special problems with regard to the transport andinstallation of elements 3, 4, 5, 6, 7. Said temporary means maysuccessively also be able to be moved from the tunnel bottom and be hungonto the tunnel lining 1 in order that the tunnel bottom will becompletely free of obstructions when e.g. the tunnel foundation 25, 28is to be cast.

The aspects of the invention can be taken further to relate to futureuse of arch elements 74, 74′ having a sandwich structure as indicated onFIGS. 28 and 29. Such sandwich structure type arch elements may beconsidered as an alternative to using elements 3, 4, 5; 3′, 4′, 5′ ofconcrete. The elements 74, 74′ can be provided by joining fireproofprofiles 70, 71, 72; 70′, 71′, 72′ into shells 73, 73′, which cansubsequently be filled with a fireproof, foamlike and relativelylightweight material. The profiles will suitably be made from metal orcomposite material or other materials which have fire resistantproperties and simultaneously are resistant against corrosion,decomposition, rust or other kinds of degradation of materialproperties.

Further, the concepts of the horizontal and vertical profiles of thearch elements of concrete, the base element, the flexible formworks, theinner formworks, ways of sealing, making interspace casts andfoundations, smoothing cast, transporting and placing structuralelements into position, and other aspects shown and described withrespect to tunnel arch forming elements of concrete are equally orsubstantially applicable to tunnel arch forming elements of a sandwichstructure.

A detailed description of these concepts and aspects of the invention isconsidered superfluous, as the description linked to the use of tunnelarch forming elements of concrete is fully instructive to the expert inthe art if it is decided to use tunnel arch forming elements of sandwichstructure.

Further, in some cases it is conceivable to use tunnel arch formingelements of concrete as well as tunnel arch forming elements of sandwichstructure, suitably having corresponding dimensions or at leastmatchable dimensions. Thus, it could be visualized for a tunnel lining 1of mainly tunnel arch forming elements of concrete to use for a fewsections thereof tunnel arch forming elements of sandwich structure, ore.g. use a sandwich type arch element as top arch element (lockingelement) instead of a top element (locking element) of concrete.Alternatively, it could also be visualized to use arch elements ofsandwich structure for the entire tunnel lining or a substantial partthereof.

As regards the sandwich structured embodiment, an outer, flexibleformwork 2 is established and the cavity 13 is closed by means of asection based lid 76 of a construction corresponding to the elements,located in lid receiving recesses 75, 75′ in the elements 74, 74′ bymeans of a locking function. The lid 76 can at the linear edge havetongue and groove for mutual stabilization, and due to the low weight ofthe elements 74, 74′, it is unproblematic to move adjacent elements 74′sideways, so that intended connection and engagement can be achieved.The interspace cast 14 can thereafter be created and the method iscompleted with a complete interspace cast 19 between rock 10 and archelements 74, 74′. Injection paths 16 in all joints can in a favourableway be established and the arch elements 74, 74′ will obviously andinherently be completely watertight.

1. A method for constructing tunnel courses which are completely orpartly surrounded by rock formations and/or are located in open air, thetunnel course in its longitudinal direction consisting of a plurality ofmutually separate, pre-fabricated tunnel arch forming structuralelements which are intended to be sealed against each other, comprising:a) installing along a tunnel course at each longitudinal side thereoftunnel element bases and cast these onto masses adjacent the bases, b)placing from recesses on the bases successively in the longitudinaldirection of the tunnel course with mutual distance self-supportivesections each consisting of at least two of said tunnel arch formingelements, wherein the tunnel arch forming elements are made of concreteor sandwich structure, c) arranging at the outside of the sections atthe opening therebetween an outer, flexible formwork, d) arrangingformwork equipment across the opening between the sections at the insideof the sections, e) injecting concrete through the formwork equipmentinto a space defined by adjacent tunnel arch forming element sections,said outer flexible formwork and said formwork equipment, so thatinjected concrete expands the outer, flexible formwork outwardly andlaterally at the outside of the tunnel course, and f) letting theinjected concrete harden.
 2. The method according to claim 1, the tunnelcourse being surrounded by rock masses, wherein feature a) furtherincludes providing the base with a skirt attached thereto along a faceof the base facing the inside of the tunnel course, the skirt beingconfigured to form a flexible formwork, and fixedly casting the baseinto place by filling concrete into a space bordered by the base,neighbouring rock masses and the skirt.
 3. The method according to claim1, wherein said tunnel arch forming elements are made of concrete andprovided on their outside with a watertight membrane.
 4. The methodaccording to claim 1, wherein the outer flexible formwork is provided byusing two longitudinal skirts at the upright edges of adjacent tunnelarch forming element, and interconnecting the neighbouring skirts toform the flexible formwork.
 5. The method according to claim 1, whereineach skirt is configured as a net, wherein concrete is injected intosaid space of which the flexible formwork forms a part until filled byconcrete, and wherein some concrete is allowed to penetrate the flexibleformwork provided by the interconnected net configured skirts.
 6. Themethod according to claim 4, the tunnel course being surrounded by rockmasses, further comprising letting the injected concrete press theflexible formwork to expand in order to contact a portion of adjacentrock mass.
 7. The method according to claim 1, comprising after thehardening of concrete in feature f) injecting via pre-arranged injectionpath in upright contact faces on the tunnel arch forming elementssealing mass between the injected, hardened concrete and the adjacenttunnel sections.
 8. The method according to claim 1, comprisinginjecting, via pre-arranged injection path at contact faces on thetunnel arch forming elements in direction of the tunnel course, sealingmass between adjacent elements of a tunnel section.
 9. The methodaccording to claim 1, wherein a compressible, open-pore mat is locatedbetween contact faces of the tunnel arch forming elements in thedirection of the tunnel course, and wherein sealing mass is injected viathe mat into the space between the contact faces.
 10. The methodaccording to claim 1, further providing a puncturable mat or cushionstructure containing sealing mass between opposite edge faces of thetunnel elements located in the direction of the tunnel course, and uponjoining the elements to form a tunnel section thereby puncturing the mator cushion structure to form a sealing between the opposite contactfaces.
 11. The method according to claim 1, wherein in a recess of thebases there is located a puncturable mat or cushion structure containingsealing mass to interact with lowermost elements of a tunnel section,and causing the mat or cushion structure to be punctured when thelowermost elements enter the respective recess.
 12. The method accordingto claim 1, comprising prior to step b) locating in recesses in thebases a fluid spreading mat, and injecting therein a sealing mass tospread the sealing mass in a space between the recesses and lowermostelements of a tunnel section entered into the recesses.
 13. The methodaccording to claim 1, the tunnel course being surrounded by rock masses,further comprising injecting into cavities between the tunnel sectionsand the rock masses filler means in the form of concrete or loose fillermaterial.
 14. The method according to claim 1, the tunnel course beinglocated in open air, further comprising applying concrete or othercovering means to the outside of tunnel sections formed by tunnel archforming elements.
 15. The method according to claim 1, wherein,following feature f), the tunnel course is completed by casting a tunnelfoundation after a membrane is established on a smoothing cast on a bedformed by rock or filler material.
 16. A structural element for use inmanufacturing a tunnel course according to the method of claim 1,wherein the element is of concrete or a sandwich structure, and whereinthe element on the outside thereof at either edge to be positionedupright and extending in a direction transversely of the longitudinaldirection of the tunnel and the element, is provided with a first,outer, flexible formwork half which is configured to be interconnectablewith a corresponding second, outer, flexible formwork half on aneighbouring further structural element when said further structuralelement is positioned next to the first mentioned element, to form aflexible formwork for receiving concrete injected between the adjacentelements and into the flexible formwork.
 17. The structural elementaccording to claim 16, wherein the structural element is made ofconcrete, and wherein its outside face is provided with a watertightmembrane.
 18. The structural element according to claim 16, wherein saidouter, flexible formwork halves each consists of attached skirtconfigured as a net, injectable concrete being locatable in a spacedefined by the interconnected, flexible formwork halves and oppositeupright side edges of adjacent tunnel arch forming structural elements.19. The structural element according to claim 18, wherein the net has amesh width which is small enough to prevent the largest sized addedmaterial of the injected concrete to penetrate the net configuredflexible formwork, and large enough to allow smaller sized parts of theadded material over at least a part of the injection period to penetratethe flexible formwork.
 20. The structural element according to claim 16,configured for a tunnel lining surrounded by rock masses, wherein theflexible formwork has a property of flexibility which allows injectedconcrete to press the flexible formwork to come to rest against aportion of the rock mass.
 21. The structural element according to claim16, comprising an injection path moulded-in or arranged in the contactfaces of the structural element which extend transversely of the tunnelcourse, the injection path capable of causing sealing mass to beinjected into a space between injected, hardened concrete forming aninterspace cast and tunnel arch forming elements adjacent thereto. 22.The structural element according to claim 16, wherein an injection path,located in at least one of the contact faces of the structural elementwhich extends in the direction of the tunnel course, is provided toallow injection of sealing mass between contact faces of adjacentelements which extend in such a direction.
 23. The structural elementaccording to claim 16, wherein in a space between contact faces ofelements extending in the direction of the tunnel course, there isarrangable a compressible, open-pore mat capable of receiving sealingmass to seal said space.
 24. The structural element according to claim16, wherein sealing in a space between contact faces of elementsextending in the direction of the tunnel course is provided by apuncturable mat or cushion structure which contains a sealing mass andto be located in said space.
 25. The structural element according toclaim 16, further comprising a puncturable mat and cushion structurecontaining sealing mass to provide sealing between lowermost elements ofthe tunnel arch forming elements and corresponding base elements belowshaped to receive a lowermost end of said lowermost elements.